It is known that the epidermal, or outer layers of human skin can be caused to peel by applying preparations to remove dead skin and to wound underlying living skin tissue. The beneficial result of such skin peeling is that when underlying layers of skin are exposed, the underlying skin is relatively free of age lines, superficial wrinkles, acne scarring, dryness, pigment spots, aging spots, acne lesions, and, with an appropriate topical composition, without the same relative degree of hyperpigmentation as compared to the same skin before a topical peeling composition was applied.
Removing old, dead surface skin cells exposes younger underlying skin tissue, which looks more youthful in part because it is smoother and reflects light more readily, thus rendering a "healthy glow" appearance. Removal of the buildup of dead skin cells is critical to producing younger-looking skin because the dead cell buildup is partly responsible for the rough, dry look associated with superficial fine lines, crow's feet, wrinkles and the like.
Chemical skin peeling is closely related to the art of skin exfoliation. Chemical skin peeling involves chemically contacting and wounding the living skin tissue found below the surface layer of dead skin cells. To accomplish this, the surface dead cells must be either removed or penetrated by the chemical peeling agents. The agents loosen the bonds between dead skin cells and underlying living tissue and stimulate the living skin tissue to form new collagen and to metabolically remove dead cells and detritus. In contrast, skin exfoliation involves only contact with and removal of all or a portion of the surface dead skin, without affecting the underlying living skin tissue. The difference between skin peeling and skin exfoliation is thus one of degree rather than of kind.
Peeling and exfoliation of the skin may be accomplished with the same chemical agents, and exfoliation is a more gentle skin treatment process than chemical peeling, since exfoliation removes only dead skin cells from the skin surface and does not wound living cells.